Dynamometer



June 9, 1925. '1,541,083

' C. L. WALKER DYNAMOMETER Filed Apri114, 1924 2 Smeets-sheet 1 Inventor June 9, 1925.

C. L. WALKER DYNAMOMETER Filed April 14. 1924 2 Sheets-Sheety 2v Patented June 9, .1925.

UNITED STATES PATENT oFFl'cE.'l

CLINTON WALKER, OF PIEDMONT, CALIFORNIA.

nYNAMoMETEn.

Application ledApril 14, 1924. ,Serial No. 706,225.

To aZZ 'who/m12?? may concern:

Be it known that I, CLINTON L. WALKER,

` and especially to that type-employing a fan or ,propeller asa resistance or braking medium.

The general idea of employing afan or propeller fortesting the horse-power of an engine or ofl connecting the engine to a propeller to impose a working load thereon -1s old as asnumber of dynamometers of this type are on the market and ih use today, but they are not entirely satisfactory as they usually depend upon a careful` calibration of the propellers and changing of the propellers when testing engines or motors of different sizes or .horse-power.

AIt might further be stated that calibrated propellers are otherwise unsatisfactory as they are dependent upon atmospheric condi. tions both as to pressure and moisture content, and as these conditions change from day to day andeven from hour to hour considerable trouble is encountered. Changes in atmospheric conditionsmay, of course, be allowed foi' and taken into considera-tion when making computations, but they impose additional work and technical skill and! as such are impractical when the average test-ing room" is taken into consideration.

The obfject of the present invention is to.v

generally improve and simplify the construction and operation o-f dynamometers of the character described and to overcome the objections abo-ve referred to; to provide a propeller which is adjustable to a consid-` erable rangev or difference in horse-power;

.to entirelyobviate the necessity of employ*- ing a calibrated propeller; Vto vprovide a d mountin for the motor to betested, which is pivota ly supported and which tilts on ,its

pivots due to the reaction set up between the propeller and the motor; and further, to

provide means for simultaneously indicating the speed' or revolutions per minute of the motor andlvthe pull or reaction transmitted to the tilting fra-me, thus yrendering it possible to instantly compute the horse-f power of va motor at any speed and without considering atmospheric conditions or otherwise. v f

The invention more specifically stated embodies an uncalibrated propeller, a.l frame for the reception of the motor, a trunnion support for theframe to permit tilting of the frame when reaction is set upbetween the propeller and the motor, a scale whereby the load or vreaction is indicated, and.y a`

tachometer or revolution counter.

With this equipment, horse-power may be computed at any speed without hanging the propeller or .considering atmospheric condition-s; the horse-power being computed by multiplyingthe revolutions per minute by the load indicated on the scale in pounds, and dividing this product by 33000 or some other suitable number as will hereinafter bes described, having reference to the accompanying` specification and drawings, in

which- Fig. l is a perspective view of the dynamometer and the trunnion supported frame upon which the motor is supported when a horse-power test is being made. y

Fig. 2 isa side elevation of the' propeller, the trunnion supported frame. etc., said side elevation being partially in Section and also showing the posltion` of the motor when undergoing a test.

Fig. 3 is an enlarged detailview of the adjustable ,cross-bar;

Referring to the drawings in detaihand particularly to-Fig. 1, A indicates, in eneral, the propeller, B the shaft to whi it 'is attached, C the frame upon which vthe motor is placed when undergoingla test, D

standards upon which the frameis support ed, and E trunnion bearings formed at the upper ends thereof which serve the function o-f forming a pivotal support for the frame and the motor positioned thereon.

The propeller is club shaped, as shown lin Fig. 1, and is suitably secured to the shaft B by allange 2 and bolts 3. Theclub is con structedl of wood or any other lsuitable matethef'club and fan blades or disksl 5 are secured thereto by'means of bolts 6. F v

The frame C consists of a pair of side bars 7 constructed of angle iron or the like,

spaced bearings 12. The shaft B extends' through.. the bearin s 12 and also through bearings 13 and 14 ormed in the cross-bars 8 and 9, respectively. nThe standard dis- .posed at the opposite end is similarly forked to form a pair of bearings 15, and a shaft 16 extendsthrough these bearings and also through bearings 17 formed in the crossbar 10. T he shafts B and 10 thus form trunnion bearings or supports for the frame,

which permits free tilting movement thereof.

The shaft 1G is provided with a pulley 18 and this may be driven from an electric motor 19 or other suitable source of power through means of a belt 20; the beltdrive being only employed when running in a motor, and when conducting a friction te,c as will hereinafter be described.

The frame is otherwise provided with a suitable form of tachometer, as shown at 21, by which the revolutions of the propeller and motor maybe visibly indicated, and it is furthermore provided.v with adjustable weights 22 and a scale 2,3; the scale being attached to the cross-amil) and to an overhead support, not here shown, by means of a cable 24; the scale indicating in pounds the pull or reaction of the motor when under test and the tachometer the revolutions; the amounts indicated being multiplied. and divided by 3300001 any other suitable number when computing the horse-power.

The frame is otherwise'provided with a cross-arm generally indicated at F. -This arm is vertlcally adjustable and it supports a central clamp, generally indicated at G, which is provided for the rece tion of the bearing of the motor to be teste The cross-member F is perhaps best illustrated in Fig. 3. It consists of bearing members 25 secured to the side frames 7. These bearings are internally threaded for the reception of bolts 26. These bolts are laterallyv adjustable and are secured when adjusted by means of lock-nuts 27. The inner ends of the bolts form bearing members for links 28; the .inks being pivotally attached to the bolts at their outer ends and to a bearing clamp 29 at their inner ends. This bearing clamp is made in two sections as shown; the upper section being adjustable and being secured by means of bolts and nuts 30; that is, the rear bearing hub or extension on diiferent motors varies in diameter and the adjustment rovided .takes ca're of such variations. T e general adjustability of the cross-member F furthermore takes care of motors of the three point suspension type and practically any type of motor can thus be placed on the frame. If a four-point suspension type is being tested, the motor will be bolted to the side frames 7, but if a three-point suspension is employed, the forward end of. the motor will be su ported by the cross-arms and the rear end by the bearing clamp G. Again, if the crank shaft of the motor does not alignwith the cross-members 8 and 9, or in other words the shaft B, it is possible to,

position plates or shims between the' cross members and the side frames so as to raise the same, or it is possible to provide offset cross-arms where it isdesired to lower the shaft B.

In actual operation the motor, whether of tl'ie three or the four point suspension type, ise placed on the frame and suitably secured by' means ofbolts or the'like. The crank shaft is then bolted to the'shaft B by the coupling indicated at 40 and the motor when so positioned is then balanced for pivotal movement aboutthe trunnion bearings; this being accomplished by attac-hin one or more adjustable weights `such as s own at 22. The blades 5' are then ositioned to afford the proper resistance fldr the motor to be tested and it is then only necessary to start the motorand torun 1t at any speed or revolutions per minute desired. The `reaction between the motor and the fan causes .-a tilting movement of the frame and this tilting movement exerts a ull on the scale 23. The scale will thus in icate the pull in pounds, while the tachometer will indicate lthe number of revolutions. The numbers thus indicated are multiplied with each other and the product divided by 33000. In the present instance the 'number 3000 is preferred as the scale is attached to the crossarm 9 at a point which measures 21 inches plus a few tlriisandths. In'other words the point of attachment presents a lever arm of such length tliat'the numeral 3000 may be employed as a substitute Lfor 33000. Thus, by` multiplying the revolutions per minute with thev pull inlpounds indicated on' the scale and dividing this product by 3000, the actual horse-powerproduced is immediately obtained.

The 'use of a calibrated propeller is obviated; atmospheric conditions need not be considered, and propellers of various. sizes are obviated, as the blades 5 may be adjusted by moving them inwardly or outwardly on the club as desired. Thus enginesof various sizes and horse-power may be taken care of. The shaftpl may be coupled tothe crank shaft in any suitable manner when it is desired to run it in previous to testing or otherwise, and it is for this reason that the belt is, of course, disconnected whe fpower test is being made vand the shaft "16 then merelyjfunctions as one of the trunnion bearings.

While certain features ofthe present ini y/claims I similarly wish it understood that the materials and finish of the several parts employed may be such as the experience and judgment of the man facturer may dictate or various uses ma d mand.

' By referring to v,i l of the drawings it will' be notedthat the cross-bar 9 is provided with two perforations such as indicated at 23si and 23". When the scale 23 is attached to one side, a horse-power reading isv obtained by the reaction` of the motor under its own power. When the-scale 23 is attached to the other side and the motor is driven by the pulley- 18, vthe friction load in the motor is measured and the horse-power consumed is computed in the same manner as for a powertest. It is customary to run the `friction test immediately following a power test so as to get the same speed and.

y the same engine temperatures and the oil power.

in the same condition as for the power test, .Having -determined the brake horse-power and the friction horse-power, the indicated horse-power is determined -by adding the brake horse-power and the friction *horse- It might stated that it-is important to measure and knowv the friction produced in a'motor as .many 'designs are .discarded on laccount of excessive'friction.

Thus by obtaining bothy it' is possible to determine whether 'the motor' is practical when considered fromboth angles.

Havingthus described my invention', what I claim and desire vto secure by Letters-yatent is- .1. A device of the character described;-

comprising a pivotally supported frame for the reception o-f a motor, a shaft extendingv through the pivotal support7 meanspermitting the motor to be connected to said shaft to rotate the same, a resistance member rotaable with Vthe shaft and attached-,thereto, and means f orresistingtilting movement of the frame;

I 2' A 4delle@ 0f the `character described," comprising a pivotally supported frame for the reception of fa motor, a shaft lextending through the pivotal support, means permitting the motor to be connected to said shaft to rotate the same, a resistance member rotatable with the shaftand attached thereto, and means' for resisting tilting movement 'of the frame, and for measuring the resistance in'pounds. p

3. A device of the character described, comprising a pivotally supported frame for the reception of. a motor, a shaft extending through the pivotal support, means permitting the motor to be connected to 'said shaft to rotate the same, a resistancemember rotatable with the shaft and attached thereto,

means for resisting tilting movement of the opposite end and connecting the side bars y bearingmembers formed on the -respective cross-bars, a pair of standards, vbearings formed at the upper ends of the standards, a shaft, extending through the bearings of 'the first named cross-bars and lone of the standards, and journalled in the respective bearings, a second shaft extending through the bearings of the other standard and the bearings of the last named cross-barsaid shaft and the first named shaft forming `a trunnion support for the frame, and said frame adapted to receive a motor, means for connecting the motor with the first named shaft so that the motor may rotatethe same, aV resistance member adapted to be secured to said shaft, and ascale attached to one side of the frame for resisting tilting of the frame about the trunnion bearings, and for visibly indicating the resistance in pounds.

5. A device of the characterdescribed, comprising a rectangular shaped frame', comprising a pair of side bars, .a pair ofcrossbars disposed at one end and connecting the side bars, a cross-bar disposedat the opposite end and connecting the side bars, bearing members formed on the respective crossbars, Aa pair of standards, bearing formed at the upper ends of the standards, a shaft extending through the bearings of the first named cross-bars and one of the standards,

and journalled in 'the respective bearings, a second shaft extending through the bearings of the/other standards and the bearings of the last named cross-bar, said'shaft and the first named shaft forming a. trunnion support for. -the frame and :said frame adapted to receive 'a motor,- means for connectlng the motor with the first named shaft so-that the motor may rotate the same, 'ai

resistance member adapted to be secured to said shaft, ascale attached to oneside of the frame for resisting tilting of thel frame about the trunnon bearing and for visibly indicating theV resistance in pounds, and thereto, means for ,rotating theconnected meatns for balancing the motor and the shafts to determine the frlctionproduced Iv frame. v in the motor, and means for resisting tilting 6. A device of the character described, movement of the frame caused by reaction 5 comprising;` a pivotally supported frame for 0f the HlOtOl and fOI measuring the leSiSZ- the reception of a motor, a shaft extending ance in pounds. through the pivotal support, means permtting the motor crank shaft to be connected CLINTON L. WALKER. 

